Modern vehicles, such as aircraft, often include head-up displays (HUDs) that project various symbols and information onto a transparent display, or image combiner, through which a user (e.g., the pilot) may simultaneously view the exterior. Traditional HUDs incorporate fixed image combiners located above the instrument panel on the windshield of the aircraft, or directly between the windshield and the pilot's head.
More recently, “head-mounted” HUDs have been increasingly developed that utilize image combiners, such as near-to-eye (NTE) displays, coupled to the helmet or headset of the pilot that moves with the changing position and angular orientation of the pilot's head. Although an advantage of head-mounted HUDs is that the information displayed may be visible to the pilot regardless of the position or orientation of his or her head, there may circumstances in which the pilot would prefer that the information on the NTE display not be visible, such as when the pilot is attempting to view the terrain with as little visible obstruction as possible, or when the pilot is viewing a display on the instrument panel (i.e., a “head-down” display).
In this sense, traditional HUDS utilizing fixed image combiners offer the advantage that the information displayed is typically only visible when the pilot's head is directly in front of the image combiner. That is, if the pilot leans to the side to look around the image combiner, the information on the HUD is no longer visible. However, such physical movement may make it more difficult to for the pilot to otherwise operate the aircraft.
In other implementations, representations of an outside field of view can be shown on head down displays (HDDs), along with overlaid imagery such as might be used on a traditional HUD.
Accordingly, it is desirable to provide a method and system for operating a display device, such as a traditional HUD, a NTE display, or a HDD displaying a representative field of view along with an overlay, in such a way as to improve the balance of the visibility of the information on the HUD and the image information over which the HUD image is overlaid, for example the outside view. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.